Session pooling and statement handles

Question

Hi there,
I have a large multi-threaded application (perhaps >100 threads). Each thread is continuously processing events (very high volumes) which involves some manipulation and some database operations (from a fixed set of possible operations).
I am using session pooling but what I want to know is, Should I:
(a) Prepare my fixed set of statement handles up front at program start-up when I'm creating the session pool and then reuse the statement handles in each event processing thread (also, is this thread safe ? even if it is, all threads would be contending on the same statement handles)
or
(b) Prepare the statement handle for each event which presumably will exploit the statement cache on the session pool. This would also mean not having statement handles shared between threads thus removing any thread contention issues.
I think (b) is the option for me, but does anyone have any thoughts ?

Answer 1

With a), one would think it's OK, but I would hate to find out that it's not thread safe by accident.
But anyway, with b) the cost of allocating private statement handles in each thread seems very low. The memory required for the statement handle plus its bind and define handles could very well be below 8k per statement. If you've got say, 5 statements * 100 threads, you're only looking at around 4MB overall.
Finally, you might want to make sure that the session pool statement cache is working by checking the values for 'executions' and 'parse_calls' in V$SQL for your statements.